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Commit 7b0411ef authored by Willem de Bruijn's avatar Willem de Bruijn Committed by David S. Miller
Browse files

virtio-net: clean tx descriptors from rx napi 



Amortize the cost of virtual interrupts by doing both rx and tx work
on reception of a receive interrupt if tx napi is enabled. With
VIRTIO_F_EVENT_IDX, this suppresses most explicit tx completion
interrupts for bidirectional workloads.

Signed-off-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ea7735d9

drivers/net/virtio_net.c

+21 −0
Original line number Diff line number Diff line
@@ -1075,12 +1075,33 @@ static void free_old_xmit_skbs(struct send_queue *sq) 
	u64_stats_update_end(&stats->tx_syncp);

}



static void virtnet_poll_cleantx(struct receive_queue *rq)

{

	struct virtnet_info *vi = rq->vq->vdev->priv;

	unsigned int index = vq2rxq(rq->vq);

	struct send_queue *sq = &vi->sq[index];

	struct netdev_queue *txq = netdev_get_tx_queue(vi->dev, index);



	if (!sq->napi.weight)

		return;



	if (__netif_tx_trylock(txq)) {

		free_old_xmit_skbs(sq);

		__netif_tx_unlock(txq);

	}



	if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS)

		netif_tx_wake_queue(txq);

}



static int virtnet_poll(struct napi_struct *napi, int budget)

{

	struct receive_queue *rq =

		container_of(napi, struct receive_queue, napi);

	unsigned int received;



	virtnet_poll_cleantx(rq);



	received = virtnet_receive(rq, budget);



	/* Out of packets? */